Finish off fixing up the memleaks (I think). Added the beginnings of

some if-then-else-fi support (nonfunctional and turned off)
 -Erik

3 files changed, 369 insertions, 114 deletions

diff --git a/lash.c b/lash.c
index 6029eaa5c..b2d1d43d3 100644
--- a/lash.c
+++ b/lash.c
@@ -27,6 +27,7 @@
 
 
 #define BB_FEATURE_SH_BACKTICKS
+//#define BB_FEATURE_SH_IF_EXPRESSIONS
 
 
 
@@ -55,6 +56,14 @@ enum redirectionType { REDIRECT_INPUT, REDIRECT_OVERWRITE,
         REDIRECT_APPEND
 };
 
+#define REGULAR_JOB_CONTEXT             0x1
+#define IF_EXP_CONTEXT                  0x2
+#define THEN_EXP_CONTEXT                0x4
+#define ELSE_EXP_CONTEXT                0x8
+
+enum jobContext { REGULAR_APP, IF_CONTEXT, THEN_CONTEXT
+};
+
 struct jobSet {
         struct job *head;                       /* head of list of running jobs */
         struct job *fg;                         /* current foreground job */
@@ -86,12 +95,12 @@ struct job {
         struct childProgram *progs;     /* array of programs in job */
         struct job *next;                       /* to track background commands */
         int stoppedProgs;                       /* number of programs alive, but stopped */
+        int jobContext;                         /* bitmask defining current context */
 };
 
 struct builtInCommand {
         char *cmd;                                      /* name */
         char *descr;                            /* description */
-        char *usage;                            /* usage */
         int (*function) (struct job *, struct jobSet * jobList);        /* function ptr */
 };
 
@@ -107,6 +116,12 @@ static int builtin_export(struct job *cmd, struct jobSet *junk);
 static int builtin_source(struct job *cmd, struct jobSet *jobList);
 static int builtin_unset(struct job *cmd, struct jobSet *junk);
 static int builtin_read(struct job *cmd, struct jobSet *junk);
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+static int builtin_if(struct job *cmd, struct jobSet *junk);
+static int builtin_then(struct job *cmd, struct jobSet *junk);
+static int builtin_else(struct job *cmd, struct jobSet *junk);
+static int builtin_fi(struct job *cmd, struct jobSet *junk);
+#endif
 
 
 /* function prototypes for shell stuff */
@@ -122,30 +137,38 @@ static int busy_loop(FILE * input);
  * can change global variables in the parent shell process but they will not
  * work with pipes and redirects; 'unset foo | whatever' will not work) */
 static struct builtInCommand bltins[] = {
-        {"bg", "Resume a job in the background", "bg [%%job]", builtin_fg_bg},
-        {"cd", "Change working directory", "cd [dir]", builtin_cd},
-        {"exit", "Exit from shell()", "exit", builtin_exit},
-        {"fg", "Bring job into the foreground", "fg [%%job]", builtin_fg_bg},
-        {"jobs", "Lists the active jobs", "jobs", builtin_jobs},
-        {"export", "Set environment variable", "export [VAR=value]", builtin_export},
-        {"unset", "Unset environment variable", "unset VAR", builtin_unset},
-        {"read", "Input environment variable", "read [VAR]", builtin_read},
-        {NULL, NULL, NULL, NULL}
+        {"bg", "Resume a job in the background", builtin_fg_bg},
+        {"cd", "Change working directory", builtin_cd},
+        {"exit", "Exit from shell()", builtin_exit},
+        {"fg", "Bring job into the foreground", builtin_fg_bg},
+        {"jobs", "Lists the active jobs", builtin_jobs},
+        {"export", "Set environment variable", builtin_export},
+        {"unset", "Unset environment variable", builtin_unset},
+        {"read", "Input environment variable", builtin_read},
+        {NULL, NULL, NULL}
 };
 
 /* Table of forking built-in functions (things that fork cannot change global
  * variables in the parent process, such as the current working directory) */
 static struct builtInCommand bltins_forking[] = {
-        {"env", "Print all environment variables", "env", builtin_env},
-        {"pwd", "Print current directory", "pwd", builtin_pwd},
-        {".", "Source-in and run commands in a file", ". filename", builtin_source},
-        {"help", "List shell built-in commands", "help", builtin_help},
-        {NULL, NULL, NULL, NULL}
+        {"env", "Print all environment variables", builtin_env},
+        {"pwd", "Print current directory", builtin_pwd},
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+        {"if", NULL, builtin_if},
+        {"then", NULL, builtin_then},
+        {"else", NULL, builtin_else},
+        {"fi", NULL, builtin_fi},
+#endif
+        {".", "Source-in and run commands in a file", builtin_source},
+        {"help", "List shell built-in commands", builtin_help},
+        {NULL, NULL, NULL}
 };
 
 static char *prompt = "# ";
 static char *cwd;
 static char *local_pending_command = NULL;
+static char *promptStr = NULL;
+static struct jobSet jobList = { NULL, NULL };
 
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
 void win_changed(int junk)
@@ -256,9 +279,13 @@ static int builtin_help(struct job *dummy, struct jobSet *junk)
         fprintf(stdout, "\nBuilt-in commands:\n");
         fprintf(stdout, "-------------------\n");
         for (x = bltins; x->cmd; x++) {
+                if (x->descr==NULL)
+                        continue;
                 fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
         }
         for (x = bltins_forking; x->cmd; x++) {
+                if (x->descr==NULL)
+                        continue;
                 fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
         }
         fprintf(stdout, "\n\n");
@@ -339,6 +366,44 @@ static int builtin_read(struct job *cmd, struct jobSet *junk)
         return (res);
 }
 
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+/* Built-in handler for 'if' commands */
+static int builtin_if(struct job *cmd, struct jobSet *junk)
+{
+        cmd->jobContext |= IF_EXP_CONTEXT;
+        printf("Hit an if -- jobContext=%d\n", cmd->jobContext);
+        return TRUE;
+}
+
+/* Built-in handler for 'then' (part of the 'if' command) */
+static int builtin_then(struct job *cmd, struct jobSet *junk)
+{
+        if (cmd->jobContext & IF_EXP_CONTEXT) {
+                fprintf(stderr, "unexpected token `then'\n");
+                fflush(stderr);
+                return FALSE;
+        }
+        cmd->jobContext |= THEN_EXP_CONTEXT;
+        printf("Hit an then -- jobContext=%d\n", cmd->jobContext);
+        return TRUE;
+}
+
+/* Built-in handler for 'else' (part of the 'if' command) */
+static int builtin_else(struct job *cmd, struct jobSet *junk)
+{
+        printf("Hit an else\n");
+        cmd->jobContext |= ELSE_EXP_CONTEXT;
+        return TRUE;
+}
+
+/* Built-in handler for 'fi' (part of the 'if' command) */
+static int builtin_fi(struct job *cmd, struct jobSet *junk)
+{
+        printf("Hit an fi\n");
+        return TRUE;
+}
+#endif
+
 /* Built-in '.' handler (read-in and execute commands from file) */
 static int builtin_source(struct job *cmd, struct jobSet *junk)
 {
@@ -471,7 +536,6 @@ static int getCommand(FILE * source, char *command)
         if (source == stdin) {
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
                 int len;
-                char *promptStr;
                 len=fprintf(stdout, "%s %s", cwd, prompt);
                 fflush(stdout);
                 promptStr=(char*)xmalloc(sizeof(char)*(len+1));
@@ -587,8 +651,9 @@ static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobLi
            Getting clean memory relieves us of the task of NULL 
            terminating things and makes the rest of this look a bit 
            cleaner (though it is, admittedly, a tad less efficient) */
-        job->cmdBuf = command = calloc(1, 2*strlen(*commandPtr) + 1);
+        job->cmdBuf = command = calloc(2*strlen(*commandPtr) + 1, sizeof(char));
         job->text = NULL;
+        job->jobContext = REGULAR_JOB_CONTEXT;
 
         prog = job->progs;
         prog->numRedirections = 0;
@@ -863,7 +928,7 @@ static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobLi
 
 static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int outPipe[2])
 {
-        struct job *job;
+        struct job *theJob;
         int i;
         int nextin, nextout;
         int pipefds[2];                         /* pipefd[0] is for reading */
@@ -957,33 +1022,33 @@ static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int
 
         newJob->pgrp = newJob->progs[0].pid;
 
-        /* find the ID for the job to use */
+        /* find the ID for the theJob to use */
         newJob->jobId = 1;
-        for (job = jobList->head; job; job = job->next)
-                if (job->jobId >= newJob->jobId)
-                        newJob->jobId = job->jobId + 1;
+        for (theJob = jobList->head; theJob; theJob = theJob->next)
+                if (theJob->jobId >= newJob->jobId)
+                        newJob->jobId = theJob->jobId + 1;
 
-        /* add the job to the list of running jobs */
+        /* add the theJob to the list of running jobs */
         if (!jobList->head) {
-                job = jobList->head = malloc(sizeof(*job));
+                theJob = jobList->head = malloc(sizeof(*theJob));
         } else {
-                for (job = jobList->head; job->next; job = job->next);
-                job->next = malloc(sizeof(*job));
-                job = job->next;
+                for (theJob = jobList->head; theJob->next; theJob = theJob->next);
+                theJob->next = malloc(sizeof(*theJob));
+                theJob = theJob->next;
         }
 
-        *job = *newJob;
-        job->next = NULL;
-        job->runningProgs = job->numProgs;
-        job->stoppedProgs = 0;
+        *theJob = *newJob;
+        theJob->next = NULL;
+        theJob->runningProgs = theJob->numProgs;
+        theJob->stoppedProgs = 0;
 
         if (inBg) {
-                /* we don't wait for background jobs to return -- append it 
-                   to the list of backgrounded jobs and leave it alone */
-                printf("[%d] %d\n", job->jobId,
+                /* we don't wait for background theJobs to return -- append it 
+                   to the list of backgrounded theJobs and leave it alone */
+                printf("[%d] %d\n", theJob->jobId,
                            newJob->progs[newJob->numProgs - 1].pid);
         } else {
-                jobList->fg = job;
+                jobList->fg = theJob;
 
                 /* move the new process group into the foreground */
                 /* suppress messages when run from /linuxrc mag@sysgo.de */
@@ -1037,7 +1102,6 @@ static int busy_loop(FILE * input)
 {
         char *command;
         char *nextCommand = NULL;
-        struct jobSet jobList = { NULL, NULL };
         struct job newJob;
         pid_t  parent_pgrp;
         int i;
@@ -1070,7 +1134,8 @@ static int busy_loop(FILE * input)
                                 newJob.numProgs) {
                                 int pipefds[2] = {-1,-1};
                                 runCommand(&newJob, &jobList, inBg, pipefds);
-                        } else {
+                        }
+                        else {
                                 free(command);
                                 command = (char *) calloc(BUFSIZ, sizeof(char));
                                 nextCommand = NULL;
@@ -1079,7 +1144,7 @@ static int busy_loop(FILE * input)
                         /* a job is running in the foreground; wait for it */
                         i = 0;
                         while (!jobList.fg->progs[i].pid ||
-                                   jobList.fg->progs[i].isStopped) i++;
+                                   jobList.fg->progs[i].isStopped == 1) i++;
 
                         waitpid(jobList.fg->progs[i].pid, &status, WUNTRACED);
 
@@ -1128,6 +1193,22 @@ static int busy_loop(FILE * input)
 }
 
 
+#ifdef BB_FEATURE_CLEAN_UP
+void free_memory(void)
+{
+        if (promptStr)
+                free(promptStr);
+        if (cwd)
+                free(cwd);
+        if (local_pending_command)
+                free(local_pending_command);
+
+        if (jobList.fg && !jobList.fg->runningProgs) {
+                removeJob(&jobList, jobList.fg);
+        }
+}
+#endif
+
 
 int shell_main(int argc, char **argv)
 {
@@ -1137,6 +1218,10 @@ int shell_main(int argc, char **argv)
         cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
         getcwd(cwd, sizeof(char)*MAX_LINE);
 
+#ifdef BB_FEATURE_CLEAN_UP
+        atexit(free_memory);
+#endif
+
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
         cmdedit_init();
         signal(SIGWINCH, win_changed);
diff --git a/sh.c b/sh.c
index 6029eaa5c..b2d1d43d3 100644
--- a/sh.c
+++ b/sh.c
@@ -27,6 +27,7 @@
 
 
 #define BB_FEATURE_SH_BACKTICKS
+//#define BB_FEATURE_SH_IF_EXPRESSIONS
 
 
 
@@ -55,6 +56,14 @@ enum redirectionType { REDIRECT_INPUT, REDIRECT_OVERWRITE,
         REDIRECT_APPEND
 };
 
+#define REGULAR_JOB_CONTEXT             0x1
+#define IF_EXP_CONTEXT                  0x2
+#define THEN_EXP_CONTEXT                0x4
+#define ELSE_EXP_CONTEXT                0x8
+
+enum jobContext { REGULAR_APP, IF_CONTEXT, THEN_CONTEXT
+};
+
 struct jobSet {
         struct job *head;                       /* head of list of running jobs */
         struct job *fg;                         /* current foreground job */
@@ -86,12 +95,12 @@ struct job {
         struct childProgram *progs;     /* array of programs in job */
         struct job *next;                       /* to track background commands */
         int stoppedProgs;                       /* number of programs alive, but stopped */
+        int jobContext;                         /* bitmask defining current context */
 };
 
 struct builtInCommand {
         char *cmd;                                      /* name */
         char *descr;                            /* description */
-        char *usage;                            /* usage */
         int (*function) (struct job *, struct jobSet * jobList);        /* function ptr */
 };
 
@@ -107,6 +116,12 @@ static int builtin_export(struct job *cmd, struct jobSet *junk);
 static int builtin_source(struct job *cmd, struct jobSet *jobList);
 static int builtin_unset(struct job *cmd, struct jobSet *junk);
 static int builtin_read(struct job *cmd, struct jobSet *junk);
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+static int builtin_if(struct job *cmd, struct jobSet *junk);
+static int builtin_then(struct job *cmd, struct jobSet *junk);
+static int builtin_else(struct job *cmd, struct jobSet *junk);
+static int builtin_fi(struct job *cmd, struct jobSet *junk);
+#endif
 
 
 /* function prototypes for shell stuff */
@@ -122,30 +137,38 @@ static int busy_loop(FILE * input);
  * can change global variables in the parent shell process but they will not
  * work with pipes and redirects; 'unset foo | whatever' will not work) */
 static struct builtInCommand bltins[] = {
-        {"bg", "Resume a job in the background", "bg [%%job]", builtin_fg_bg},
-        {"cd", "Change working directory", "cd [dir]", builtin_cd},
-        {"exit", "Exit from shell()", "exit", builtin_exit},
-        {"fg", "Bring job into the foreground", "fg [%%job]", builtin_fg_bg},
-        {"jobs", "Lists the active jobs", "jobs", builtin_jobs},
-        {"export", "Set environment variable", "export [VAR=value]", builtin_export},
-        {"unset", "Unset environment variable", "unset VAR", builtin_unset},
-        {"read", "Input environment variable", "read [VAR]", builtin_read},
-        {NULL, NULL, NULL, NULL}
+        {"bg", "Resume a job in the background", builtin_fg_bg},
+        {"cd", "Change working directory", builtin_cd},
+        {"exit", "Exit from shell()", builtin_exit},
+        {"fg", "Bring job into the foreground", builtin_fg_bg},
+        {"jobs", "Lists the active jobs", builtin_jobs},
+        {"export", "Set environment variable", builtin_export},
+        {"unset", "Unset environment variable", builtin_unset},
+        {"read", "Input environment variable", builtin_read},
+        {NULL, NULL, NULL}
 };
 
 /* Table of forking built-in functions (things that fork cannot change global
  * variables in the parent process, such as the current working directory) */
 static struct builtInCommand bltins_forking[] = {
-        {"env", "Print all environment variables", "env", builtin_env},
-        {"pwd", "Print current directory", "pwd", builtin_pwd},
-        {".", "Source-in and run commands in a file", ". filename", builtin_source},
-        {"help", "List shell built-in commands", "help", builtin_help},
-        {NULL, NULL, NULL, NULL}
+        {"env", "Print all environment variables", builtin_env},
+        {"pwd", "Print current directory", builtin_pwd},
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+        {"if", NULL, builtin_if},
+        {"then", NULL, builtin_then},
+        {"else", NULL, builtin_else},
+        {"fi", NULL, builtin_fi},
+#endif
+        {".", "Source-in and run commands in a file", builtin_source},
+        {"help", "List shell built-in commands", builtin_help},
+        {NULL, NULL, NULL}
 };
 
 static char *prompt = "# ";
 static char *cwd;
 static char *local_pending_command = NULL;
+static char *promptStr = NULL;
+static struct jobSet jobList = { NULL, NULL };
 
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
 void win_changed(int junk)
@@ -256,9 +279,13 @@ static int builtin_help(struct job *dummy, struct jobSet *junk)
         fprintf(stdout, "\nBuilt-in commands:\n");
         fprintf(stdout, "-------------------\n");
         for (x = bltins; x->cmd; x++) {
+                if (x->descr==NULL)
+                        continue;
                 fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
         }
         for (x = bltins_forking; x->cmd; x++) {
+                if (x->descr==NULL)
+                        continue;
                 fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
         }
         fprintf(stdout, "\n\n");
@@ -339,6 +366,44 @@ static int builtin_read(struct job *cmd, struct jobSet *junk)
         return (res);
 }
 
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+/* Built-in handler for 'if' commands */
+static int builtin_if(struct job *cmd, struct jobSet *junk)
+{
+        cmd->jobContext |= IF_EXP_CONTEXT;
+        printf("Hit an if -- jobContext=%d\n", cmd->jobContext);
+        return TRUE;
+}
+
+/* Built-in handler for 'then' (part of the 'if' command) */
+static int builtin_then(struct job *cmd, struct jobSet *junk)
+{
+        if (cmd->jobContext & IF_EXP_CONTEXT) {
+                fprintf(stderr, "unexpected token `then'\n");
+                fflush(stderr);
+                return FALSE;
+        }
+        cmd->jobContext |= THEN_EXP_CONTEXT;
+        printf("Hit an then -- jobContext=%d\n", cmd->jobContext);
+        return TRUE;
+}
+
+/* Built-in handler for 'else' (part of the 'if' command) */
+static int builtin_else(struct job *cmd, struct jobSet *junk)
+{
+        printf("Hit an else\n");
+        cmd->jobContext |= ELSE_EXP_CONTEXT;
+        return TRUE;
+}
+
+/* Built-in handler for 'fi' (part of the 'if' command) */
+static int builtin_fi(struct job *cmd, struct jobSet *junk)
+{
+        printf("Hit an fi\n");
+        return TRUE;
+}
+#endif
+
 /* Built-in '.' handler (read-in and execute commands from file) */
 static int builtin_source(struct job *cmd, struct jobSet *junk)
 {
@@ -471,7 +536,6 @@ static int getCommand(FILE * source, char *command)
         if (source == stdin) {
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
                 int len;
-                char *promptStr;
                 len=fprintf(stdout, "%s %s", cwd, prompt);
                 fflush(stdout);
                 promptStr=(char*)xmalloc(sizeof(char)*(len+1));
@@ -587,8 +651,9 @@ static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobLi
            Getting clean memory relieves us of the task of NULL 
            terminating things and makes the rest of this look a bit 
            cleaner (though it is, admittedly, a tad less efficient) */
-        job->cmdBuf = command = calloc(1, 2*strlen(*commandPtr) + 1);
+        job->cmdBuf = command = calloc(2*strlen(*commandPtr) + 1, sizeof(char));
         job->text = NULL;
+        job->jobContext = REGULAR_JOB_CONTEXT;
 
         prog = job->progs;
         prog->numRedirections = 0;
@@ -863,7 +928,7 @@ static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobLi
 
 static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int outPipe[2])
 {
-        struct job *job;
+        struct job *theJob;
         int i;
         int nextin, nextout;
         int pipefds[2];                         /* pipefd[0] is for reading */
@@ -957,33 +1022,33 @@ static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int
 
         newJob->pgrp = newJob->progs[0].pid;
 
-        /* find the ID for the job to use */
+        /* find the ID for the theJob to use */
         newJob->jobId = 1;
-        for (job = jobList->head; job; job = job->next)
-                if (job->jobId >= newJob->jobId)
-                        newJob->jobId = job->jobId + 1;
+        for (theJob = jobList->head; theJob; theJob = theJob->next)
+                if (theJob->jobId >= newJob->jobId)
+                        newJob->jobId = theJob->jobId + 1;
 
-        /* add the job to the list of running jobs */
+        /* add the theJob to the list of running jobs */
         if (!jobList->head) {
-                job = jobList->head = malloc(sizeof(*job));
+                theJob = jobList->head = malloc(sizeof(*theJob));
         } else {
-                for (job = jobList->head; job->next; job = job->next);
-                job->next = malloc(sizeof(*job));
-                job = job->next;
+                for (theJob = jobList->head; theJob->next; theJob = theJob->next);
+                theJob->next = malloc(sizeof(*theJob));
+                theJob = theJob->next;
         }
 
-        *job = *newJob;
-        job->next = NULL;
-        job->runningProgs = job->numProgs;
-        job->stoppedProgs = 0;
+        *theJob = *newJob;
+        theJob->next = NULL;
+        theJob->runningProgs = theJob->numProgs;
+        theJob->stoppedProgs = 0;
 
         if (inBg) {
-                /* we don't wait for background jobs to return -- append it 
-                   to the list of backgrounded jobs and leave it alone */
-                printf("[%d] %d\n", job->jobId,
+                /* we don't wait for background theJobs to return -- append it 
+                   to the list of backgrounded theJobs and leave it alone */
+                printf("[%d] %d\n", theJob->jobId,
                            newJob->progs[newJob->numProgs - 1].pid);
         } else {
-                jobList->fg = job;
+                jobList->fg = theJob;
 
                 /* move the new process group into the foreground */
                 /* suppress messages when run from /linuxrc mag@sysgo.de */
@@ -1037,7 +1102,6 @@ static int busy_loop(FILE * input)
 {
         char *command;
         char *nextCommand = NULL;
-        struct jobSet jobList = { NULL, NULL };
         struct job newJob;
         pid_t  parent_pgrp;
         int i;
@@ -1070,7 +1134,8 @@ static int busy_loop(FILE * input)
                                 newJob.numProgs) {
                                 int pipefds[2] = {-1,-1};
                                 runCommand(&newJob, &jobList, inBg, pipefds);
-                        } else {
+                        }
+                        else {
                                 free(command);
                                 command = (char *) calloc(BUFSIZ, sizeof(char));
                                 nextCommand = NULL;
@@ -1079,7 +1144,7 @@ static int busy_loop(FILE * input)
                         /* a job is running in the foreground; wait for it */
                         i = 0;
                         while (!jobList.fg->progs[i].pid ||
-                                   jobList.fg->progs[i].isStopped) i++;
+                                   jobList.fg->progs[i].isStopped == 1) i++;
 
                         waitpid(jobList.fg->progs[i].pid, &status, WUNTRACED);
 
@@ -1128,6 +1193,22 @@ static int busy_loop(FILE * input)
 }
 
 
+#ifdef BB_FEATURE_CLEAN_UP
+void free_memory(void)
+{
+        if (promptStr)
+                free(promptStr);
+        if (cwd)
+                free(cwd);
+        if (local_pending_command)
+                free(local_pending_command);
+
+        if (jobList.fg && !jobList.fg->runningProgs) {
+                removeJob(&jobList, jobList.fg);
+        }
+}
+#endif
+
 
 int shell_main(int argc, char **argv)
 {
@@ -1137,6 +1218,10 @@ int shell_main(int argc, char **argv)
         cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
         getcwd(cwd, sizeof(char)*MAX_LINE);
 
+#ifdef BB_FEATURE_CLEAN_UP
+        atexit(free_memory);
+#endif
+
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
         cmdedit_init();
         signal(SIGWINCH, win_changed);
diff --git a/shell/lash.c b/shell/lash.c
index 6029eaa5c..b2d1d43d3 100644
--- a/shell/lash.c
+++ b/shell/lash.c
@@ -27,6 +27,7 @@
 
 
 #define BB_FEATURE_SH_BACKTICKS
+//#define BB_FEATURE_SH_IF_EXPRESSIONS
 
 
 
@@ -55,6 +56,14 @@ enum redirectionType { REDIRECT_INPUT, REDIRECT_OVERWRITE,
         REDIRECT_APPEND
 };
 
+#define REGULAR_JOB_CONTEXT             0x1
+#define IF_EXP_CONTEXT                  0x2
+#define THEN_EXP_CONTEXT                0x4
+#define ELSE_EXP_CONTEXT                0x8
+
+enum jobContext { REGULAR_APP, IF_CONTEXT, THEN_CONTEXT
+};
+
 struct jobSet {
         struct job *head;                       /* head of list of running jobs */
         struct job *fg;                         /* current foreground job */
@@ -86,12 +95,12 @@ struct job {
         struct childProgram *progs;     /* array of programs in job */
         struct job *next;                       /* to track background commands */
         int stoppedProgs;                       /* number of programs alive, but stopped */
+        int jobContext;                         /* bitmask defining current context */
 };
 
 struct builtInCommand {
         char *cmd;                                      /* name */
         char *descr;                            /* description */
-        char *usage;                            /* usage */
         int (*function) (struct job *, struct jobSet * jobList);        /* function ptr */
 };
 
@@ -107,6 +116,12 @@ static int builtin_export(struct job *cmd, struct jobSet *junk);
 static int builtin_source(struct job *cmd, struct jobSet *jobList);
 static int builtin_unset(struct job *cmd, struct jobSet *junk);
 static int builtin_read(struct job *cmd, struct jobSet *junk);
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+static int builtin_if(struct job *cmd, struct jobSet *junk);
+static int builtin_then(struct job *cmd, struct jobSet *junk);
+static int builtin_else(struct job *cmd, struct jobSet *junk);
+static int builtin_fi(struct job *cmd, struct jobSet *junk);
+#endif
 
 
 /* function prototypes for shell stuff */
@@ -122,30 +137,38 @@ static int busy_loop(FILE * input);
  * can change global variables in the parent shell process but they will not
  * work with pipes and redirects; 'unset foo | whatever' will not work) */
 static struct builtInCommand bltins[] = {
-        {"bg", "Resume a job in the background", "bg [%%job]", builtin_fg_bg},
-        {"cd", "Change working directory", "cd [dir]", builtin_cd},
-        {"exit", "Exit from shell()", "exit", builtin_exit},
-        {"fg", "Bring job into the foreground", "fg [%%job]", builtin_fg_bg},
-        {"jobs", "Lists the active jobs", "jobs", builtin_jobs},
-        {"export", "Set environment variable", "export [VAR=value]", builtin_export},
-        {"unset", "Unset environment variable", "unset VAR", builtin_unset},
-        {"read", "Input environment variable", "read [VAR]", builtin_read},
-        {NULL, NULL, NULL, NULL}
+        {"bg", "Resume a job in the background", builtin_fg_bg},
+        {"cd", "Change working directory", builtin_cd},
+        {"exit", "Exit from shell()", builtin_exit},
+        {"fg", "Bring job into the foreground", builtin_fg_bg},
+        {"jobs", "Lists the active jobs", builtin_jobs},
+        {"export", "Set environment variable", builtin_export},
+        {"unset", "Unset environment variable", builtin_unset},
+        {"read", "Input environment variable", builtin_read},
+        {NULL, NULL, NULL}
 };
 
 /* Table of forking built-in functions (things that fork cannot change global
  * variables in the parent process, such as the current working directory) */
 static struct builtInCommand bltins_forking[] = {
-        {"env", "Print all environment variables", "env", builtin_env},
-        {"pwd", "Print current directory", "pwd", builtin_pwd},
-        {".", "Source-in and run commands in a file", ". filename", builtin_source},
-        {"help", "List shell built-in commands", "help", builtin_help},
-        {NULL, NULL, NULL, NULL}
+        {"env", "Print all environment variables", builtin_env},
+        {"pwd", "Print current directory", builtin_pwd},
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+        {"if", NULL, builtin_if},
+        {"then", NULL, builtin_then},
+        {"else", NULL, builtin_else},
+        {"fi", NULL, builtin_fi},
+#endif
+        {".", "Source-in and run commands in a file", builtin_source},
+        {"help", "List shell built-in commands", builtin_help},
+        {NULL, NULL, NULL}
 };
 
 static char *prompt = "# ";
 static char *cwd;
 static char *local_pending_command = NULL;
+static char *promptStr = NULL;
+static struct jobSet jobList = { NULL, NULL };
 
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
 void win_changed(int junk)
@@ -256,9 +279,13 @@ static int builtin_help(struct job *dummy, struct jobSet *junk)
         fprintf(stdout, "\nBuilt-in commands:\n");
         fprintf(stdout, "-------------------\n");
         for (x = bltins; x->cmd; x++) {
+                if (x->descr==NULL)
+                        continue;
                 fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
         }
         for (x = bltins_forking; x->cmd; x++) {
+                if (x->descr==NULL)
+                        continue;
                 fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
         }
         fprintf(stdout, "\n\n");
@@ -339,6 +366,44 @@ static int builtin_read(struct job *cmd, struct jobSet *junk)
         return (res);
 }
 
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+/* Built-in handler for 'if' commands */
+static int builtin_if(struct job *cmd, struct jobSet *junk)
+{
+        cmd->jobContext |= IF_EXP_CONTEXT;
+        printf("Hit an if -- jobContext=%d\n", cmd->jobContext);
+        return TRUE;
+}
+
+/* Built-in handler for 'then' (part of the 'if' command) */
+static int builtin_then(struct job *cmd, struct jobSet *junk)
+{
+        if (cmd->jobContext & IF_EXP_CONTEXT) {
+                fprintf(stderr, "unexpected token `then'\n");
+                fflush(stderr);
+                return FALSE;
+        }
+        cmd->jobContext |= THEN_EXP_CONTEXT;
+        printf("Hit an then -- jobContext=%d\n", cmd->jobContext);
+        return TRUE;
+}
+
+/* Built-in handler for 'else' (part of the 'if' command) */
+static int builtin_else(struct job *cmd, struct jobSet *junk)
+{
+        printf("Hit an else\n");
+        cmd->jobContext |= ELSE_EXP_CONTEXT;
+        return TRUE;
+}
+
+/* Built-in handler for 'fi' (part of the 'if' command) */
+static int builtin_fi(struct job *cmd, struct jobSet *junk)
+{
+        printf("Hit an fi\n");
+        return TRUE;
+}
+#endif
+
 /* Built-in '.' handler (read-in and execute commands from file) */
 static int builtin_source(struct job *cmd, struct jobSet *junk)
 {
@@ -471,7 +536,6 @@ static int getCommand(FILE * source, char *command)
         if (source == stdin) {
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
                 int len;
-                char *promptStr;
                 len=fprintf(stdout, "%s %s", cwd, prompt);
                 fflush(stdout);
                 promptStr=(char*)xmalloc(sizeof(char)*(len+1));
@@ -587,8 +651,9 @@ static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobLi
            Getting clean memory relieves us of the task of NULL 
            terminating things and makes the rest of this look a bit 
            cleaner (though it is, admittedly, a tad less efficient) */
-        job->cmdBuf = command = calloc(1, 2*strlen(*commandPtr) + 1);
+        job->cmdBuf = command = calloc(2*strlen(*commandPtr) + 1, sizeof(char));
         job->text = NULL;
+        job->jobContext = REGULAR_JOB_CONTEXT;
 
         prog = job->progs;
         prog->numRedirections = 0;
@@ -863,7 +928,7 @@ static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobLi
 
 static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int outPipe[2])
 {
-        struct job *job;
+        struct job *theJob;
         int i;
         int nextin, nextout;
         int pipefds[2];                         /* pipefd[0] is for reading */
@@ -957,33 +1022,33 @@ static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int
 
         newJob->pgrp = newJob->progs[0].pid;
 
-        /* find the ID for the job to use */
+        /* find the ID for the theJob to use */
         newJob->jobId = 1;
-        for (job = jobList->head; job; job = job->next)
-                if (job->jobId >= newJob->jobId)
-                        newJob->jobId = job->jobId + 1;
+        for (theJob = jobList->head; theJob; theJob = theJob->next)
+                if (theJob->jobId >= newJob->jobId)
+                        newJob->jobId = theJob->jobId + 1;
 
-        /* add the job to the list of running jobs */
+        /* add the theJob to the list of running jobs */
         if (!jobList->head) {
-                job = jobList->head = malloc(sizeof(*job));
+                theJob = jobList->head = malloc(sizeof(*theJob));
         } else {
-                for (job = jobList->head; job->next; job = job->next);
-                job->next = malloc(sizeof(*job));
-                job = job->next;
+                for (theJob = jobList->head; theJob->next; theJob = theJob->next);
+                theJob->next = malloc(sizeof(*theJob));
+                theJob = theJob->next;
         }
 
-        *job = *newJob;
-        job->next = NULL;
-        job->runningProgs = job->numProgs;
-        job->stoppedProgs = 0;
+        *theJob = *newJob;
+        theJob->next = NULL;
+        theJob->runningProgs = theJob->numProgs;
+        theJob->stoppedProgs = 0;
 
         if (inBg) {
-                /* we don't wait for background jobs to return -- append it 
-                   to the list of backgrounded jobs and leave it alone */
-                printf("[%d] %d\n", job->jobId,
+                /* we don't wait for background theJobs to return -- append it 
+                   to the list of backgrounded theJobs and leave it alone */
+                printf("[%d] %d\n", theJob->jobId,
                            newJob->progs[newJob->numProgs - 1].pid);
         } else {
-                jobList->fg = job;
+                jobList->fg = theJob;
 
                 /* move the new process group into the foreground */
                 /* suppress messages when run from /linuxrc mag@sysgo.de */
@@ -1037,7 +1102,6 @@ static int busy_loop(FILE * input)
 {
         char *command;
         char *nextCommand = NULL;
-        struct jobSet jobList = { NULL, NULL };
         struct job newJob;
         pid_t  parent_pgrp;
         int i;
@@ -1070,7 +1134,8 @@ static int busy_loop(FILE * input)
                                 newJob.numProgs) {
                                 int pipefds[2] = {-1,-1};
                                 runCommand(&newJob, &jobList, inBg, pipefds);
-                        } else {
+                        }
+                        else {
                                 free(command);
                                 command = (char *) calloc(BUFSIZ, sizeof(char));
                                 nextCommand = NULL;
@@ -1079,7 +1144,7 @@ static int busy_loop(FILE * input)
                         /* a job is running in the foreground; wait for it */
                         i = 0;
                         while (!jobList.fg->progs[i].pid ||
-                                   jobList.fg->progs[i].isStopped) i++;
+                                   jobList.fg->progs[i].isStopped == 1) i++;
 
                         waitpid(jobList.fg->progs[i].pid, &status, WUNTRACED);
 
@@ -1128,6 +1193,22 @@ static int busy_loop(FILE * input)
 }
 
 
+#ifdef BB_FEATURE_CLEAN_UP
+void free_memory(void)
+{
+        if (promptStr)
+                free(promptStr);
+        if (cwd)
+                free(cwd);
+        if (local_pending_command)
+                free(local_pending_command);
+
+        if (jobList.fg && !jobList.fg->runningProgs) {
+                removeJob(&jobList, jobList.fg);
+        }
+}
+#endif
+
 
 int shell_main(int argc, char **argv)
 {
@@ -1137,6 +1218,10 @@ int shell_main(int argc, char **argv)
         cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
         getcwd(cwd, sizeof(char)*MAX_LINE);
 
+#ifdef BB_FEATURE_CLEAN_UP
+        atexit(free_memory);
+#endif
+
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
         cmdedit_init();
         signal(SIGWINCH, win_changed);